Centred TVD schemes for hyperbolic conservation laws

New first- and high-order centred methods for conservation lawsare presented. Convenient TVD conditions for constructing centredTVD schemes are then formulated and some useful results areproved. Two families of centred TVD schemes are constructedand extended to nonlinear systems. Some numerical results arealso presented.     

Quantification of Mycophenolic Acid and Citrinin Produced by Penicillium sp. Using 1H NMR

This study proposes a simple methodology to construct the production curves of mycophenolic acid by Penicillium sp. (CASP5) and citrinin by Penicillium sp. (CATL1.1) in the crude extract, without any purification. The quantification of the compounds was done by ¹H nuclear magnetic resonance (NMR) using the signal integration and an internal standard, N,N-dimethylformamide. Fungi were cultivated for a period of 20 days and quantification of the metabolites in the extracts was done starting from time zero, 2 days and after this period in an interval of 4 days. The maximum production of mycophenolic acid and citrinin was obtained at 12 and 8 days of fermentation, respectively. These results show that the ¹H NMR technique was efficient to define the production curves of mycophenolic acid and citrinin directly in the crude extracts. In addition, the technique made it possible to evaluate the purity degree of the substances obtained in the extraction process. Furthermore, this is the first study that uses the ¹H NMR technique to determine the production curves of secondary metabolites.     

First X-rays from a novel full-scale superconducting undulator at ANKA: Higher magnetic peak field than cryogenic permanent magnet devices

The ANKA Synchrotron Radiation Facility at KIT and Babcock Noell GmbH (BNG) are pursuing a Research & Development program on superconducting undulators (SCUs). The collaboration focuses on conduction-cooled SCUs with NbTi superconductor coils and a variable vacuum gap. Since SCUs can reach higher magnetic peak fields than permanent magnet in-vacuum insertion devices, including cryogenic ones (for the same gap and period length), they have the potential to increase the spectral range, brilliance and flux of existing state-of-the-art devices.     

Synthesis and total 1H- and 13C-NMR assignment of cephem derivatives for use in ADEPT approaches

We report the synthesis and total NMR characterization of 5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylic acid-3-[[[(4'-nitrophenoxy)carbonyl]oxy]-methyl]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (5), a new cephalosporin derivative. This compound can be used as the carrier of a wide range of drugs containing an amino group. The preparation of the intermediate product, 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl 4-(6-methoxyquinolin-8-ylamino)pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (6), as well as the synthesis of the antimalarial primaquine prodrug 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl 4-(6-methoxyquinolin-8-ylamino)pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]- 5-dioxide (7) are also described, together with their total (1)H- and (13)C-NMR assignments.     

Evaluation of biodiesel-diesel blends quality using H NMR and chemometrics

In this work, the use of ¹H NMR spectroscopy and statistical approach to the evaluation of biodiesel-diesel blends quality is described. Forty-six mixtures of oil-diesel, biodiesel-diesel, and oil-biodiesel-diesel were analyzed by ¹H NMR and such data were employed to design four predictive models. Thirty-six mixtures were used in the calibration set and the others in the validation. The PCR and PLS models were evaluated through statistical parameters.Briefly, PLS and PCR models were suitable for the prediction of biodiesel and oil concentration in mineral diesel. Specially, in higher concentration the predicted values were quite similar to the real ones. This fact was evidenced by the low relative errors of high concentrated samples; this means that the prediction of low concentrated samples will probably show high deviation. Therefore, ¹H NMR-PLS and ¹H NMR-PCR methods are fairly useful for the quality control of biodiesel-diesel blends, particularly they are suitable for prediction of concentrations greater than 2%.